I have tried to go through the settings.
It asks for an e-mail and a password.
Assuming it was a new registration I used both "example" and "example@iduokan.com" as the e-mail and a password of my choosing.
All I could get was an exclamation mark and some writing in chinese that I can not understand.

I haven't used Duokan for a long time hence don't remember exactly. However what I remember is that I registered through the settings page. You could probably create an account then use it to login to the system through the related item on the settings page.

I haven't used Duokan for a long time hence don't remember exactly. However what I remember is that I registered through the settings page. You could probably create an account then use it to login to the system through the related item on the settings page.

OK, I've done it.
So all you need to do is enter one of your e-mail accounts (as in example@gmail.com), enter a password (it doesnt have to be the exact same one the one for the e-mail account you just provided) and select ok.

Duokan will create an account for you (as in example_98@iduokan.com) and that's it! Works perfectly
Thanks everyone for all your help on that one.